In a multidisciplinary research effort we attempt to correlate solution conformation and crystalline conformation of peptide hormones and other biologically active compounds to their biology. Within the framework we correlate structural and conformational information with the mode of hormone interaction with various binding proteins (reflected, for example, in the physiological and pharmacological properties of these hormones, in their immunological properties and their affinities for carrier proteins) and the enzymatic inactivation mechanisms in various tissues and by purified enzymes. This information is helpful to design hormone analogs of therapeutic value. The possible physiological role of hormones as prohormones for hypothalamic-hypophysiotropic factors and other biologically active peptides will be $vestigated. The methods used in these studies include chemical synthesis of unlabeled and labeled compounds, bioassay, conformational analysis, X-ray crystallography, enzyme studies, structure determination and clinical investigations involving physiologists, biochemists, and clinicians.